If their choice of pro-euthanasia "bio-ethicist" Peter Singer as an inspiration doesn't tip you off to PETA's true aim, then this story may illustrate that it isn't about being nice to animals.
Wesley J. Smiths's piece on PETA last week in NRO applies his considerable intellect to the weird ethical gymnastics of the "animal rights" movement:
I have long perceived the animal-liberation movement to be deeply misanthropic, and Bottum’s theory explains why. If indeed “we are all animals,” then there is no hierarchy of moral worth. Since human contact with animals is seen, by definition, as causing animals to suffer, and since all suffering is evil — yet, only humans can act in an evil way — then the belief that cattle ranching equals Auschwitz becomes a logical conclusion.